260 EXPLANATION Ol- THE MAPS. supposed axis. We now know that in Avhatever direction the Himalaya has been explored, its axis has been found to be be- yond the snowy peaks, and indicated by the river-heads. We have therefore in all cases of doubt represented the rivers as following the courses of valleys enclosed by mountains, and assumed that the geographical axis of a chain is indicated by its watershed. We have not hesitated to contour *he table-land of the Dekhan, so as approximately to represent a system of ranges descending from the meridional axis of the Peninsula to the eastern coast, and attaining an average elevation of 1500-2000 feet* We have also given to that axis itself a more inter- rupted and tortuous course than is usually represented; it being an error to suppose that it forms a continuous ridge of nearly uniform height parallel to the coast. Central India we have also represented as a hilly table-land, intersected by con- siderable valleys; of which there is ample evidence in surveys and the accounts of travellers. For the details of the mountain systems of East Tibet there are no authorities, but we have expressed its main features,— that of an enormously elevated mountain mass. This is proved by the statements of many intelligent Tibetans, by the Chinese geographers, by the narrative of M. Hue, and by the fact of so many of the large rivers of Asia flowing from it in several directions. To omit a feature which rivals the Himalaya in dimensions, and which exercises a paramount influence over the meteorology of Eastern Asia, would deprive our map of much of the. use we hope it may be of, in illustrating the re- lations between the vegetation and climate of India. It remains to add, that the system of spelling (which is the classical one) adopted both in the maps and the pages of our work, is rendered imperative from the fast that we hope our work may be useful to foreigners as well as to our own countrymen.